use rustc_target::spec::abi::Abi;
use std::cell::Cell;
-use std::{iter, mem, usize};
+use std::{cmp, iter, mem, usize};
use crate::const_eval::{is_const_fn, is_unstable_const_fn};
use crate::transform::check_consts::{is_lang_panic_fn, qualifs, ConstKind, Item};
/// errors when promotion of `#[rustc_args_required_const]` arguments fails.
///
/// After this pass is run, `promoted_fragments` will hold the MIR body corresponding to each
-/// newly created `StaticKind::Promoted`.
+/// newly created `Constant`.
#[derive(Default)]
pub struct PromoteTemps<'tcx> {
pub promoted_fragments: Cell<IndexVec<Promoted, BodyAndCache<'tcx>>>,
source: &'a mut BodyAndCache<'tcx>,
promoted: BodyAndCache<'tcx>,
temps: &'a mut IndexVec<Local, TempState>,
+ extra_statements: &'a mut Vec<(Location, Statement<'tcx>)>,
/// If true, all nested temps are also kept in the
/// source MIR, not moved to the promoted MIR.
candidate: Candidate,
next_promoted_id: usize,
) -> Option<BodyAndCache<'tcx>> {
- let mut operand = {
+ let mut rvalue = {
let promoted = &mut self.promoted;
let promoted_id = Promoted::new(next_promoted_id);
let tcx = self.tcx;
- let mut promoted_place = |ty, span| {
+ let mut promoted_operand = |ty, span| {
promoted.span = span;
promoted.local_decls[RETURN_PLACE] = LocalDecl::new_return_place(ty, span);
- Place {
- base: PlaceBase::Static(box Static {
- kind: StaticKind::Promoted(
- promoted_id,
+
+ Operand::Constant(Box::new(Constant {
+ span,
+ user_ty: None,
+ literal: tcx.mk_const(ty::Const {
+ ty,
+ val: ty::ConstKind::Unevaluated(
+ def_id,
InternalSubsts::identity_for_item(tcx, def_id),
+ Some(promoted_id),
),
- ty,
- def_id,
}),
- projection: List::empty(),
- }
+ }))
};
let (blocks, local_decls) = self.source.basic_blocks_and_local_decls_mut();
match candidate {
Candidate::Ref(loc) => {
let ref mut statement = blocks[loc.block].statements[loc.statement_index];
match statement.kind {
- StatementKind::Assign(box (_, Rvalue::Ref(_, _, ref mut place))) => {
+ StatementKind::Assign(box (
+ _,
+ Rvalue::Ref(ref mut region, borrow_kind, ref mut place),
+ )) => {
// Use the underlying local for this (necessarily interior) borrow.
let ty = place.base.ty(local_decls).ty;
let span = statement.source_info.span;
- Operand::Move(Place {
- base: mem::replace(&mut place.base, promoted_place(ty, span).base),
- projection: List::empty(),
- })
+ let ref_ty = tcx.mk_ref(
+ tcx.lifetimes.re_static,
+ ty::TypeAndMut { ty, mutbl: borrow_kind.to_mutbl_lossy() },
+ );
+
+ *region = tcx.lifetimes.re_static;
+
+ let mut projection = vec![PlaceElem::Deref];
+ projection.extend(place.projection);
+ place.projection = tcx.intern_place_elems(&projection);
+
+ // Create a temp to hold the promoted reference.
+ // This is because `*r` requires `r` to be a local,
+ // otherwise we would use the `promoted` directly.
+ let mut promoted_ref = LocalDecl::new_temp(ref_ty, span);
+ promoted_ref.source_info = statement.source_info;
+ let promoted_ref = local_decls.push(promoted_ref);
+ assert_eq!(self.temps.push(TempState::Unpromotable), promoted_ref);
+
+ let promoted_ref_statement = Statement {
+ source_info: statement.source_info,
+ kind: StatementKind::Assign(Box::new((
+ Place::from(promoted_ref),
+ Rvalue::Use(promoted_operand(ref_ty, span)),
+ ))),
+ };
+ self.extra_statements.push((loc, promoted_ref_statement));
+
+ Rvalue::Ref(
+ tcx.lifetimes.re_static,
+ borrow_kind,
+ Place {
+ base: mem::replace(
+ &mut place.base,
+ PlaceBase::Local(promoted_ref),
+ ),
+ projection: List::empty(),
+ },
+ )
}
_ => bug!(),
}
StatementKind::Assign(box (_, Rvalue::Repeat(ref mut operand, _))) => {
let ty = operand.ty(local_decls, self.tcx);
let span = statement.source_info.span;
- mem::replace(operand, Operand::Copy(promoted_place(ty, span)))
+
+ Rvalue::Use(mem::replace(operand, promoted_operand(ty, span)))
}
_ => bug!(),
}
TerminatorKind::Call { ref mut args, .. } => {
let ty = args[index].ty(local_decls, self.tcx);
let span = terminator.source_info.span;
- let operand = Operand::Copy(promoted_place(ty, span));
- mem::replace(&mut args[index], operand)
+
+ Rvalue::Use(mem::replace(&mut args[index], promoted_operand(ty, span)))
}
// We expected a `TerminatorKind::Call` for which we'd like to promote an
// argument. `qualify_consts` saw a `TerminatorKind::Call` here, but
};
assert_eq!(self.new_block(), START_BLOCK);
- self.visit_operand(
- &mut operand,
+ self.visit_rvalue(
+ &mut rvalue,
Location { block: BasicBlock::new(0), statement_index: usize::MAX },
);
let span = self.promoted.span;
- self.assign(RETURN_PLACE, Rvalue::Use(operand), span);
+ self.assign(RETURN_PLACE, rvalue, span);
Some(self.promoted)
}
}
let mut promotions = IndexVec::new();
+ let mut extra_statements = vec![];
for candidate in candidates.into_iter().rev() {
match candidate {
Candidate::Repeat(Location { block, statement_index })
let initial_locals =
iter::once(LocalDecl::new_return_place(tcx.types.never, body.span)).collect();
+ let mut promoted = Body::new(
+ IndexVec::new(),
+ // FIXME: maybe try to filter this to avoid blowing up
+ // memory usage?
+ body.source_scopes.clone(),
+ initial_locals,
+ IndexVec::new(),
+ 0,
+ vec![],
+ body.span,
+ vec![],
+ body.generator_kind,
+ );
+ promoted.ignore_interior_mut_in_const_validation = true;
+
let promoter = Promoter {
- promoted: BodyAndCache::new(Body::new(
- IndexVec::new(),
- // FIXME: maybe try to filter this to avoid blowing up
- // memory usage?
- body.source_scopes.clone(),
- initial_locals,
- IndexVec::new(),
- 0,
- vec![],
- body.span,
- vec![],
- body.generator_kind,
- )),
+ promoted: BodyAndCache::new(promoted),
tcx,
source: body,
temps: &mut temps,
+ extra_statements: &mut extra_statements,
keep_original: false,
};
}
}
+ // Insert each of `extra_statements` before its indicated location, which
+ // has to be done in reverse location order, to not invalidate the rest.
+ extra_statements.sort_by_key(|&(loc, _)| cmp::Reverse(loc));
+ for (loc, statement) in extra_statements {
+ body[loc.block].statements.insert(loc.statement_index, statement);
+ }
+
// Eliminate assignments to, and drops of promoted temps.
let promoted = |index: Local| temps[index] == TempState::PromotedOut;
for block in body.basic_blocks_mut() {
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